Fossil fuel is a general term for buried combustible geologic deposits of organic materials, formed from decayed plants and animals that have been converted to crude oil, coal, natural gas, or heavy oils by exposure to heat and pressure in the earth's crust over hundreds of millions of years. Fossil fuels are a finite, non-renewable resource.
Many industries, including plastics and chemical manufacturers, rely heavily on the availability of hydrocarbons as a feedstock for their manufacturing processes.
PCT Pub. Nos. 2008/151149 describe methods and materials for cultivating microalgae for the production of oil, extraction of microbial oil, and production of food, food oil, fuels, and other oleochemicals from oil produced by oleaginous microbes.
One important oleochemical application is the production of industrial dielectric fluids, which are used for electrical insulation and cooling or heat dissipation in transformers and other electrical devices. These electrical devices include power and distribution transformers, circuit breakers, capacitors, switchgear, X-ray machines and insulating cables.
Bio-based oil, particularly high-oleic acid soybean oil, has been used as a dielectric fluid in sealed transformers since the 1990s (see Srivastava (2009) Int'l J Computer Electrical Eng, v. 1(2) pp. 212-216). Current bio-based dielectric fluids are purified, high-oleic triacylglycerols (TAGs) with incorporated additives (see U.S. Pat. No. 6,274,067 and US Patent App. Nos 20100243969 and 20080283803). For example, the primary benefits of high-oleic acid soybean oil dielectric fluid versus mineral oil-based dielectric fluid are (i) an increased fire point (2×), (ii) an increased transformer life (4-8×), and (iii) a lower cost of remediating spills due to bio-based oil's high biodegradability (>3×) and lower toxicity (see Schneider (2006) J Sci Food Agric, v. 86 pp: 1769-1780).
The primary disadvantages of bio-based oils over mineral-based oils are the oxidative instability of bio-based oils, the increased cost of procuring bio-based oils and transitioning equipment from mineral-based oils to bio-based oils see Schneider (2006), supra). Although bio-based dielectric fluids occupy a significant portion of the dielectric fluid market, mineral-oil based dielectric fluids currently dominate the market. Another significant disadvantage is the cost of production of these soy-based oils and their diversion of an important food source into non-food applications.